The California Geological
Survey (CGS) has developed highway corridor landslide
hazard maps to meet the needs of
engineers, geologists, planners, and maintenance
staff of the California Department of
Transportation (Caltrans). The project was initiated after the 1997
Mill Creek Slide closed a portion of U.S.
Highway 50 for
approximately one month. Maps prepared by CGS as
part of the emergency response and recovery from
the 1997 incident now serve as a planning and
maintenance document for developing long-term
mitigation strategies. Recognizing the value of
this product, Caltrans contracted with CGS to
develop a series of maps of selected California highway
corridors within a variety of climatological and
geological settings. The maps provide an
inventory of landslide activity along the
selected highway corridors. This big picture
perspective will benefit planning of route
improvements and lead to more effective
landslide risk mitigation for California's
highways.

CGS's response and initial evaluation of the
U.S. Highway 50 landslide (1997 Mill Creek
Slide) was described in California
Geology Magazine in 1997.
Click here to download 1997 article

Each of the reports prepared under this project
includes a description of the geologic materials
along the highway corridor, the distribution and
types of landslides, and the potential impacts
of landslides on the highway. Geologic and
landslide inventory maps are included in each
report. In most reports, Plate 1(the geologic
map) and Plate 2 (the landslide map) are
formatted into map sections that can be
downloaded and printed on 11x
17 inch size pages.